An exposed microfiche can be developed by inserting it between two closely spaced walls and then raising a seal to seal a region between the walls in which the microfiche lies. Then a pressured developing fluid, such as anhydrous ammonia at a pressure of approximately 25 psi, is applied through a passage formed in one of the walls, such as the lower wall of the chamber.
One problem often encountered with the above developing arrangement is the occurrence of an uneven flow of developing fluid to the microfiche surface which is to be developed. A microfiche often assumes a bowed-up configuration, so that its opposite end portions lie almost flat against the lower walls of the chamber, and the developing fluid cannot reach these end portions to fully develop them. Another problem which can be encountered is that the seal which must seal the region around the microfiche, can repeatedly rub against a side supporting wall and wear out.